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Bond, Van Wyk proposed the following primary characteristics for four types of
groundwater.
Group A: Highly mineraRzed chloride waters
lal Waters usually contain >3500 mg r' TDS (Bond, 1946: 1 000 - 4 000 mg r'l.
Ibl There is a high chloride content, which is generally >30% of TDS.
(cl Soda alkalinity (Na2C03 or NaHC0 3 1 is never present.
(d) High salinity water is confined to the Cretaceous beds along the Natal North Coast,
with most boreholes abandoned due to the high salinity.
Group B: Mineralized chloride waters
lal TDS values range from 750 - 2 500 mg r', although there is little difference in
percentage composition between Group A and B waters.
Ibl Waters have a relatively high chloride content averaging 40% of TDS. Van Wyk
119631 maintained that the high salinity of the groundwaters is due to wind-borne
salts derived from the Indian Ocean·.
Icl There is some difference in the composition of waters from the Stormberg lava and
Karoo sediments. Main differences include:
(il The pH of water in the Karoo sediments averages 8,1 which is greater than
in the basalt 17,11.
(iil The soda alkalinity (Na2C03 or NaHC0 3 ) of water from the Karoo sediments
is very low, while in the basalt, alkalinity averages >9%, up to 50% of
TDS.
• For a further discussion see Murgatroyd, A.L., 1983. Spatial variations in precipitation chemistry over
Natal, South Africa, South African Journal of Science. VOL 79(101, p. 408 - 410.